Slice the onion.
Place the beef roast into the base of the electric pressure cooker insert with the hot water. Add the sliced onion, salsa, ground cumin and salt and pepper over the top of the beef roast.
Steam valve: Sealing.
Cook on: Manual/High for 50 to 60 minutes. (Thicker roasts, 60 minutes; thinner roasts, 50 minutes.)
Release: Natural or Quick.
Once finished cooking, shred or slice the beef and serve over rice.
Cook the rice, as directed.
Prepare the guacamole, if needed.
Serve Instant Pot Salsa Beef Roast over rice with guacamole.